Patent GB-764727-A (GB)
Title: Radar antenna apparatus
IPC: H01Q1/18
Filed: 1955-03-02
Abstract: 764,727. Electric correspondence control systems. SPERRY CORPORATION. March 2, 1955 [April 21, 1954], No. 6181/55. Class 40 (1). [Also in Group XL (c)] Radar antenna apparatus for use on a dirigible craft, capable of providing different beam patterns, wherein the beam can be rotated about two mutually perpendicular axes, is provided with means whereby the two axes may be locked with the normally vertical and horizontal axes of the craft, or may be maintained in the true vertical and horizontal. Assembly.-The beam radiator 40 (Fig. 1) and reflector 57, 59 are supported from a frame 15 mounted on the craft by a waveguide 19 journalled at each end for rotation or oscillation about the normally vertical axis 16 by means of a motor 21 (Fig. 2) through a disc 20 which also carries a series of slip-rings co-operating with fixed brushes 22. The lower bearing of waveguide 19 comprises a wheel 25 from which extend two arms 26, 27 terminating in bearings 28, 29 defining a horizontal axis 31 for movement of the antenna apparatus consistent with the pitch axis of the craft. Energy for the radiator 40 is fed through waveguides 23, 19, 33, 32, 35, 41, 42, the waveguide 42 and radiator 40 being rotatable about the axis of waveguide 41 which constitutes a second horizontal axis 43 perpendicular to axis 31 consistent with the roll axis of the craft. Waveguide 41 is connected through universal joints to two control links 47, 48 which can be operated to rotate the antenna about axis 31 or 43. A third horizontal axis of rotation 49 is produced by bearings in the ends of a U-shaped bracket 52, attached to the waveguide 41, which supports the upper half 57 of the reflector, an extension of the bracket 52 also supporting a beam switching motor 56 which aligns the upper half reflector 57 with a bottom half 58 or 59 as required to give a pencil type beam or a fan type beam. The reflector as a whole may be tilted about the axis 49 by means of a motor 135 (Fig. 8), the amount of tilt being determined by the setting of a potentiometer 163 in the pilot control box 117, which together with potentiometer 139 forms a balanced potentiometer circuit which, when unbalanced, energizes relay 159 to cause motor 135 to run, rotating the reflector unit about axis 49, and the slider 138 of potentiometer 139 until balance is regained. During the switching from one beam pattern to the other, the radiator is stabilized about the craft axes with zero tilt. Stabilization means.-A gyro vertical 63 (Fig. 8) mounted on the frame 15 has a pick-up 64 producing a signal proportional to movement of the craft about the pitch axis, which is amplified at 68 and fed via relay 72 to a pitch motor 65 (Fig. 2) mounted on frame 15 to stabilize the pitch gimbal 66 about its axis 67. Similarly, a pick-up 92 produces a signal proportional to movement about the roll axis which s amplified at 96 and fed via relay 72 to a roll motor 93 (Fig. 1) mounted on pitch gimbal 66 to stabilize the roll gimbal 94 about its axis 95. Relay 72 is operated by a switch 116 in the pilot control box 117. The movements of gimbals 66, 94 are transmitted mechanically through the links 47, 48 to effect similar stabilization about axes 31, 43 of the reflector and radiator parts of the antenna. Hence the antenna is stabilized in space. With relay 72 in the unenergized condition the antenna is stabilized about the craft's nominal vertical and horizontal axes. A follow-up switch comprising two insulated contacts 216, 217 mounted on the frame 15 and a contact member 215 on the gimbal 66 causes motor 65 to stabilize the gimbal 66 for roll about its axis 67. Similarly follow-up switch members 210, 211, 213 produce stabilization of gimbal 94 for pitch about its axis 95. Hence the antenna is stabilized relative to the craft on which it is mounted, and is locked in this position by plungers 226, 235 co-operating with holes 228, 236, unlocking being automatically effected when switch 116 is operated to energize relay 72 and causes the antenna to be stabilized about the true vertical and horizontal axes.